The present invention relates to manufacture of electrochemical cells. More particularly, the present invention provides a method and system for a manufacturing facility for fabrication of thin film energy devices. Merely by way of example, the invention has been provided for the manufacture of lithium based cells, but it would be recognized that other materials such as zinc, silver, copper and nickel could be designed in the same or like fashion. Additionally, such batteries can be used for a variety of applications such as portable electronics (cell phones, personal digital assistants, music players, video cameras, and the like), power tools, power supplies for military use (communications, lighting, imaging and the like), power supplies for aerospace applications (power for satellites), and power supplies for vehicle applications (hybrid electric vehicles, plug-in hybrid electric vehicles, and fully electric vehicles). The design of such batteries is also applicable to cases in which the battery is not the only power supply in the system, and additional power is provided by a fuel cell, other battery, IC engine or other combustion device, capacitor, solar cell, etc.
Common electro-chemical cells often use liquid electrolytes. Such cells are typically used in many conventional applications. Alternative techniques for manufacturing electro-chemical cells include solid state cells. Such solid state cells are generally in the experimental state, have been difficult to make, and have not been successfully produced in large scale. Although promising, solid state cells have not been achieved due to limitations in cell structures and manufacturing techniques. These and other limitations have been described throughout the present specification and more particularly below.
Solid state batteries have been proven to have several advantages over conventional batteries using liquid electrolyte in lab settings. Safety is the foremost one. Solid state battery is intrinsically more stable than liquid electrolyte cells since it does not contain a liquid that causes undesirable reaction, resulting thermal runaway, and an explosion in the worst case. Solid state battery can store over 30% more energy for the same volume or over 50% more for the same mass than conventional batteries. Good cycle performance, more than 10,000 cycles, and a good high temperature stability also has been reported.
Despite of these outstanding properties of solid state batteries, there are challenges to address in the future to make this type of batteries available in the market. To exploit the compactness and high energy density, no metal housing or excessive substrate should be used. To be used in variety of applications such as consumer electronics or electric vehicle, large area and fast film deposition techniques at low cost should be developed. Also, a solid state, hybrid thin film energy storage and conversion device, such as solid-a state battery, a solid oxide fuel cell, a capacitor, a photovoltaic cell and a hybrid device of these, consists of several components of thin film layers. These thin film layers are made from different materials and of different thicknesses. The deposition rate of laying down a material using a physical vapor deposition technique to form the thin film layer varies with the material and the processing technique used. Each individual layer requires a different time to finish to make a thin film device.
The production rate of solid state batteries, in terms the number of device units made per unit time, depends on the slowest, rate-limiting processing step for the layer with the largest thickness to deposition rate ratio. Multiple deposition zones and multiple deposition chambers are used to speed up the rate-limiting processing step by distributing the deposition task in parallel to the assigned multiple zones and chambers. However, the added deposition zones and chambers increase the total capital and operational expenditure for the manufacturing facility. It is necessary to optimize the number of deposition zones and chambers to balance the competition between cost and production rate. The same optimization necessity exists for other solid state, hybrid thin film energy storage and conversion device manufacturing processing steps including chemical vapor deposition, atomic layer deposition, winding, slitting, packaging using a technique of at least but not limited to dip coating, and robotic arm operations for attaching leads, wiring, moving, handling and electronic control component assembling.
However, the existing manufacturing facilities for solid state, hybrid thin film energy storage and conversion devices, including solid-state batteries, solid oxide fuel cells, capacitors, photovoltaic cells and hybrid devices of these, are designed in an arbitrary and subjective intuition-based fashion without conducting a systematical and mathematical analysis to identify the optimal design.
From the above, it is seen that techniques for improving the charging methods and systems relating to solid state cells are highly desirable.